In the processing of food, such as large roast, other meat and large batches of vegetables, the food is substantially solid, and weighs many pounds. After the food is cooked, it is desired that the temperature be lowered as rapidly as possible, after which the temperature is maintained at a pre-selected level. The temperature to be reached and maintained is the internal temperature of the food product, since it is known that the surface temperature and the temperature of the interior may be substantially different during the chilling process, and until a stabilized and uniform temperature of the product is achieved.
To effect the above noted rapid chilling and low temperature maintenance functions, there has been provided so called "Rapid Chill Refrigerators". These refrigerators are provided with two independent refrigeration systems. One refrigeration system is known as the "Chill Refrigeration System" and the other refrigeration system is known as the "Maintenance Refrigeration System". In order to lower the temperature of the product as rapidly as possible, both refrigeration systems are employed; after a period of time, a timer set for a pre-selected time duration causes the chill refrigeration system to be cut off, thereby leaving the maintenance refrigeration system to continue in operation, so as to maintain the food product at a desired temperature.
The known rapid chill refrigerators have been provided as above noted, with an adjustable timer to control the rapid chill refrigeration system, so that it operates over a pre-selected period of time after its actuation. Such rapid chill refrigerators have also been provided with a product temperature probe, connected either to an indicator or to an alarm circuit which is in turn connected to an indicator, to thereby give either or both of a visual indication of the internal temperature of a selected product within the rapid chill refrigerator and/or to provide an alarm when the product has reached a pre-selected temperature.
A basis of utilizing a timer control circuit is that testing, as by the manufacturer, provides an indication that a certain number of food products, each averaging a certain weight, and with a beginning temperature of a certain level, has been found to require a certain length of time for the interior of the products to be chilled. The rapid chill refrigerator user sets the timer control for the period indicated by the manufacturer of the rapid chill refrigerator for the particular load.
It has now been recognized that the above procedure of testing to obtain timing information for particular food loads by the equipment manufacturer at its facility, and then the reliance on that information by the user, does not provide uniform results. This is because of factors which are encountered by the users which are different from the test product and facility. For example, the user may not be able to control the quantity of food in a given load to be rapid chilled. The elevated start temperature of the food product may differ from the tested product. Some food is air cooled between cooking and rapid chilling, so that different loads may have had different air cooling periods, thereby varying the starting temperature for the rapid chill process. Additionally, the user's environment, such as room temperature, may vary from load to load, and from the room temperature of the test facility.